There is known an operation device on which an input unit, such as a switch unit and an encoder unit, is provided. A user operates such the input unit, so that a signal is inputted to the operation device.
For example, Patent Document 1 (i.e., Japanese Laid-open Patent Publication No. 10-223090) discloses an operation device including; a plurality of switch units each including a switch; and a plurality of operation buttons each of which projects a pressing pin which turns on/off the switch. Patent Document 2 (i.e., Japanese Laid-open Patent Publication No. 10-269002) discloses a button operation device like the operation device of the Patent Document 1. Patent Document 3 (i.e., Japanese Laid-open Patent Publication No. 5-94057) discloses an operation device including; a plurality of units each of which has a plurality of operation displaying elements; and a plurality of attachment portions. In the operation device, each unit can be attached to an arbitrary position in the attachment portions. In the operation devices of the Patent Documents 1 to 3, the positions of the operation buttons or the units can be changed depending on the preference of the user.